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/*-
* Copyright (c) 2006 Sam Leffler
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Support for redirecting console msgs to gdb. We register
* a pseudo console to hook cnputc and send stuff to the gdb
* port. The only trickiness here is buffering output so this
* isn't dog slow.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/cons.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/reboot.h>
#include <sys/sysctl.h>
#include <machine/gdb_machdep.h>
#include <machine/kdb.h>
#include <gdb/gdb.h>
#include <gdb/gdb_int.h>
struct gdbcons {
int npending;
/* /2 for hex conversion, -6 for protocol glue */
char buf[GDB_BUFSZ/2 - 6];
struct callout flush;
};
static struct gdbcons state = { -1 };
static int gdbcons_enable = 0;
SYSCTL_INT(_debug, OID_AUTO, gdbcons, CTLFLAG_RW, &gdbcons_enable,
0, "copy console messages to gdb");
TUNABLE_INT("debug.gdbcons", &gdbcons_enable);
static void
gdb_cnprobe(struct consdev *cp)
{
sprintf(cp->cn_name, "gdb");
cp->cn_pri = CN_LOW; /* XXX no way to say "write only" */
}
static void
gdb_cninit(struct consdev *cp)
{
struct gdbcons *c = &state;
/* setup tx buffer and callout */
if (c->npending == -1) {
c->npending = 0;
callout_init(&c->flush, CALLOUT_MPSAFE);
cp->cn_arg = c;
}
}
static int
gdb_nogetc(struct consdev *cp)
{
return -1;
}
static void
gdb_tx_puthex(int c)
{
const char *hex = "0123456789abcdef";
gdb_tx_char(hex[(c>>4)&0xf]);
gdb_tx_char(hex[(c>>0)&0xf]);
}
static void
gdb_cnflush(void *arg)
{
struct gdbcons *gc = arg;
int i;
gdb_tx_begin('O');
for (i = 0; i < gc->npending; i++)
gdb_tx_puthex(gc->buf[i]);
gdb_tx_end();
gc->npending = 0;
}
/*
* This glop is to figure out when it's safe to use callouts
* to defer buffer flushing. There's probably a better way
* and/or an earlier point in the boot process when it's ok.
*/
static int calloutok = 0;
static void
oktousecallout(void *data __unused)
{
calloutok = 1;
}
SYSINIT(gdbhack, SI_SUB_RUN_SCHEDULER, SI_ORDER_ANY, oktousecallout, NULL)
static void
gdb_cnputc(struct consdev *cp, int c)
{
struct gdbcons *gc;
if (gdbcons_enable && gdb_cur != NULL && gdb_listening) {
gc = cp->cn_arg;
if (gc->npending != 0) {
/*
* Cancel any pending callout and flush the
* buffer if there's no space for this byte.
*/
if (calloutok)
callout_stop(&gc->flush);
if (gc->npending == sizeof(gc->buf))
gdb_cnflush(gc);
}
gc->buf[gc->npending++] = c;
/*
* Flush on end of line; this is especially helpful
* during boot when we don't have callouts to flush
* the buffer. Otherwise we defer flushing; a 1/4
* second is a guess.
*/
if (c == '\n')
gdb_cnflush(gc);
else if (calloutok)
callout_reset(&gc->flush, hz/4, gdb_cnflush, gc);
}
}
/* NB: no get interface, we supply nogetc for checkc too */
CONS_DRIVER(gdb, gdb_cnprobe, gdb_cninit, NULL, gdb_nogetc, gdb_nogetc,
gdb_cnputc, NULL);
/*
* Our console device only gets attached if the system is booted
* with RB_MULTIPLE set so gdb_init also calls us to attach the
* console so we're setup regardless.
*/
void
gdb_consinit(void)
{
gdb_cnprobe(&gdb_consdev);
gdb_cninit(&gdb_consdev);
cnadd(&gdb_consdev);
}
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